Process and apparatus for producing shortening



April 14, 1959 w. DALZIEIL ETAL 2,882,155

' PROCESS AND APPARATUS FOR PRODUCING SHORTENING Filed June 9, 1955 n, l S aw? A m an mum MM ww BM WM, Firm ATTDRNEYS United. tates Patetito w PROCESS AND APPARATUS FOR PRODUCING SHORTENING William Dalziel, Bebington, and William Thornton Dow, Upton, Wirral, England, assignors to Lever Brothers Company, New York, N.Y., a corporation of Maine Application June 9, 1955, Serial No. 514,251

Claims priority, application Great Britain June 16, 1954 16 Claims. (Cl. 99-418) This invention relates to improvements in the production of shortening, and in particular to the production of an aerated shortening, such as aerated cooking fat, so as to enable it to be packed in the 'form of wrapped blocks as well as produced by a wholly continuous process.

Aerated cooking fat containing an entrained innocuous gas, such' as air, may be pre-packed for direct sale to the consumer by either wrapping a solid block of fat manually or on an automatic packing machine or by dispensing the fat as a fluid into special containers. The first method normally implies batch operation, time being required between successive chilling, texturising and packing operationstol ensure the manufacture of a product of satisfacto'ry appearance and texture, and also to ensure that the product can be packed by an automatic packing machine. The second method requires expensive rigid or semi-rigid containers, into which the fluid fat is filled. Alternatively, moulds supporting cheaper flexible containers during and atter. filling have to be used with consequent consumption oftime and labour. Various arrangements for coupling a continuously operating machine for producing plastic materials to an intermittently operating packing machine are in existence. In thesearrangements a connection is provided between the outlet of the producing machine and the inlet ofthe packing machine for conducting the material under the output pressure of the producing machine to the packing machine. Means, hereinafter referred to as pressure means, are provided for applying intermittent or constant additional'pressure to the material. When intermittent pressure is used, the pressure is applied while the packing machine is open to be charged and released while the packing machine is closed. These pressure means can serve to accommodate the material issuing from the producing machine during the period of closure of the packing machine.

,One such specification No. 590,935 where the pressure means supplies intermittent additional pressure. In the arrangement of British patent specification No. 590,935 the pressure means consist of a cylinder and piston connected as a branch to the connection between the producing machine and packing machine. While the packing machine "is closed the piston moves up the cylinderto accommodate the continued feed of material into the connection from the producing machine. When thepacking machine opens, compressed air or mechanical pressure is applied behind the piston which forces the material at increased pressure to fill the packing machine. As soon as the latter closes, the pressure behind the piston is released. .j The use of an arrangement such as that of British patent specification No. 590,935 has made possible a comarrangement is described in British patent p letely continuous process of producing and packaging material in whichthe material is producedin an apparat'us commonly known as a Votator. This type of apparatusis described onpages 702 to 708 of.A. E. Baileys book-industrial Oil and Fat Products (Inter-science Pu biishers Inc.-, New York, 1945). This Votator consists of one or more thin walled nickel tubes surrounded by a cooling medium such as evaporating liquid ammonia. The tubes (commonly known as the A-unit of the Votator). are provided with internal rotating blades which remove the thin film of chilled material from their walls. After chilling, the mixture, which is nucleated with minute fat crystals, passes to a chamber or B-unit of the Votator where crystallisation of the fat is substantially completed. In the arrangement for carrying out the completely continuous process of producing and packaging margarine, this Votator constitutes the continuously operating machine for producing plastic materials which is coupled to an intermittently operating packing machine by an 81 rangement such as that described in British patent specification No. 590,935

It is desirable to be able to produce and wrap blocks of aerated shortening such as aerated cooking fat by a wholly continuous process. However, when a Votator is coupled by an arrangement such as that described in British patent specification No. 590,935 to an intermittently operating packing machine, and the combined arrangement is used to chill and wrap blocks of fat blends normally used for preparing areated cooking fat, these blends having been suitably aerated to give the desired entrained gas content of the resultant fat, then a product is obtained which does not have the appearance normally associated with aerated cooking fat, being non-uniform in appearance and marred by dark streaks.

It is an object of the present invention to provide a C0111 tinuous process of producing and packing an aerated shortening which results in a satisfactory shortening after forming into blocks and wrapping by an automatic packing machine coupled to the producing machine and operating under pressure from the producing machine. It is a further object to provide apparatus for carrying out this process.

According to the present invention there is provided a continuous process of producing and packing an aerated shortening consisting of aerating a liquid fat with an innocuous gas, chilling a stream of the aerated fat under pressure, crystallising the stream of chilled fat, and feeding it directly under pressure to an automatic packing machine, the pressure of the chilled fat being substantially higher than that at which the crystallised fat is fed to the packing macine and being suddenly relieved before crystallisation is completed.

The pressure on the fat during chilling may be suc that substantially all the introduced gas is in solution during chilling. The packing machine should be of the type which moulds the chilled fat into blocks and wraps the blocks. The pressure on the chilled fat should be relieved to an extent which causes sufiicient introduced gas to change from the dissolved to entrained state to give a final block of fat which is uniform in appearance and not marred by dark streaksthat is to say, the appearance of the final block of fat should resemble that of a block of aerated shortening produced -by the conventional processes described above. Preferably the pressure on the fat is relieved almost immediately after cessation of chill It is preferred to agitate the fat during chilling, for example, by carrying out the chilling in'the A-unit of a Votator.

The conditions necessary to success in the foregoing operations may be realised by constricting the "stream of fat after chilling and before crystallisation is contpleted. In general terms,the greater the degree to which crystallisation advances before the constriction, the greater is the pressure required on the high pressure side of the constriction if a satisfactory aeratedand uniform product is to result. It is of primary importance that pres of the constriction should be moderate and preferably not more than 1.5 kilos/sq. cm. above atmospheric. The pressure on the high pressure side of the constriction may be between and kilos per sq. cm. Care should be taken that this pressure, that is, the pressure during chilling, does not fall'too low. If it does, some of the dissolved gas might become entrained. The presence of entrained gas'during chilling results in a lower efliciency of refrigeration. It is also of importance that crystallisation of the product as it proceeds under moderate pressure towards the packing machine should be allowed to take place with the minimum of working. To achieve this end ithas been found advisable to allow the product stream to expand into a conduit of relatively large crosssectional dimensions after its passage through the constriction and, in the case of certain fat blends, to warm the low pressure conduit externally.

After crystallisation is substantially complete, the

stream of crystallised aerated fat may pass to an intermittently operating packing machine through an arrangethem such as is described in British patent specification No. 590,935, whereby a wholly continuous process for producing and packing aerated shortening is achieved. The pressure means in the arrangement of the British patent specification only applies intermittent additional pressure. If, however, pressure means applying constant additional pressure is used, care should be taken to ensure that the constant additional pressure does not cause the total pressure of the crystallised fat to exceed that pressure which will ensure that the desired amount of gas in an entrained state is present in the final block of fat. For this reason it is preferable that the constant additional pressure does not exceed 1.5 kilos/sq. cm. The means whereby the flow of fat is constricted consists of a suitably dimensioned orifice located in the conduit connecting a chilling device in which the fat is chilled to a crystallising device in which the chilled fat is allowed to crystallise.

Thus, the present invention also provides an arrangement for carrying out the above mentioned process, which arrangement includes means for introducing an innocuous gas into liquid fat, a chilling device connected thereto for chilling a stream of aerated liquid fat, at crystallising device in which the chilled fat is allowed to crystallise, a connection between the chilling device and the crystallising device, a constriction in said connection, an intermittently operating packing machine for molding the crystallised fat into blocks and wrapping the blocks, a connection between the packing machine and the crystallising device and pressure means for applying additional pressure to any material in the connection between the packing machine and the crystallising device and serving toaccommodate material issuing from the crystallising device during the period of closure of the packing machine.

The dimensions of the constriction may be adjustable. For example, the constriction may be an orifice of adjustable dimensions which is preferably provided by a gate valve located in the conduit connecting the chilling device with the crystallising device. Any variation in processing conditions which tend to result in a streaky product may then be countered immediately by a suitable adjustment of the dimensions of the orifice.

Preferably the crystallising device which confines the crystallised fat in provided with external heating means such as a hot water jacket to assist in maintaining low pressure conditions therein for retaining the gas in the entrained state after passage through the constriction. Theconnection between the crystallising device and the packing machine may also be provided with external Heating means.

The chilling device consists preferably of the Aunit of; aVotaton and the crystallising device is preferably a eonduitsimilar to the B-unit of a Votator, such as is normally used in margarine pr duction- The invention will now be illustrated by means of the accompanying diagrammatic drawing which shows a complete system according to one embodiment of the invention for continuously processing aerated cooking fat.

Referring to the drawing, a vessel 1 for liquid fat having a jacket 22 and fitted with an agitator 23 is connected by a conduit 2 through a valve 3 to a centrifugal pump 4 the exit conduit 24 of which is controlled by a valve 5 and terminates in a ball float valve 7 in a constant level tank 6. The exit conduit 8 of the tank 6 is controlled by valve 10 and connects the tank to a positive pump 11 having any suitable variable drive. The centrifugal pump 4 is of greater capacity than positive pump 11, which controls the processing rate of the system, to ensure that a constant level of fat is maintained in the tank 6. The conduit 3 is in the form of an inverted-U for part of its length, the vertical limbs of which rise above the controlled level of liquid fat in tank 6. This arrangement results in sub-atmospheric pressure in the limbs of the inverted-U at any vertical height above the level of fat in the tank 6. At the point of lowest pressure, point A, a 0.6 cm. bore needle valve 9 open to the atmosphere is fitted. Adjustment of valve 9 permits air to flow from atmospheric pressure to the sub-atmospheric pressure at which the fat is flowing through conduit 8. Maximum air distribution'in the fat is achieved by the fitting of a 0.3 cm. diameter bore pipe 25 to the fat side of needle valve 9, this pipe 25 extending halfway along the centre of the bore of the horizontal limb of the U tube. A suitable vertical height of the inverted U tube is twenty to twenty-five cms'. above the fat level in tank 6, and any extension of this height will result in increased sensitivity of the needle valve adjustment.

When an innocuous aerating gas other than air is employed, the valve 9 may be connected to a constant pressure supply of the gas, of standard construction, not shown, and the gas flow controlled. The volume of air or other aerating gas used may be measured by a suitable flow indicator, not shown, inserted immediately before the needle valve 9.

The exit conduit 12 of the pump 11 discharges into the chilling device, this conduit being provided with a pressure gauge 26 and safety valve 27. The chilling device may consist of the tubes 13 and 13' connected together by conduit 28 and forms the A-unit of a Votator. Tubes 13 and 13' are enclosed in jackets 29 and 29' respectively containing a chilling medium and fitted with agitator-scraper blades 30 and 30' attached to rotatable shafts 31 and 31 respectively, such shafts being connected to wheels 32 and 32 driven by a source of power, not shown. The exit conduit 33 of tube 13' carries a pressure control gate valve 14 and connects tube 13 to the crystallising chamber 18. The chamber has a relatively large cross-sectional area to permit expansion of the product after restriction thereof by valve 14. It is of suitable length to permit crystallisation of the product being effectively complete upon reaching the packing machine 20. Chamber 18 is analogous to the conventional B" unit of a Votator, such as is normally used in margarine production, and is surrounded by a jacket 15 with exit and inlet conduits 16 and 17 respectively for war water. The chamber 18 is connected by a suitable arrangement of flanges 34 and 35 directly to a coupling arrangement 19,.such as that disclosed in British Patent No. 590,935. The jacket 15 surrounding crystallising device 18 extends to include coupling arrangement 19. The coupling arrangement 19 is directly connected to an intermittently operating packing machine 20 in the manner described in British Patent No. 590,935. A conveyor 21 is provided for removing wrapped packets from the vicinity of the packing machine.

The operation of the above described arrangement is as follows:

A suitable liquid fat blend at a temperature of approximately 45 C. is fed from vessel 1 by the pump 4 to tlie' const'antlevel tank 6 through conduits 2 and 24 and valves 3'and' 5." The liquid fat is drawn from the tank 6f through conduit 8 at the desired rate by the pump 11. A controlled supply of air is drawn from the atmosphere through {needle valve 9 and pipe 25 into'the fat stream in conduit"$. From the pump the fat mixture is passed through conduit 12 to tubes 13 and 13' where it is chilled. Theexit conduit 3 3'of tube 13' is an approximately 76 cms. length of tube having an internal diameter of 2.25 jc'ms' at the end of which is fitted the gate valve 14. From' the orifice created by the gate valve the product expands into the crystallising chamber 18 having heating jacketIS. The orifice formed by valve 14 creates a pressure difierential on either side thereof which may be controlled by adjustment of the size of the orifice. Maintenance of low pressure and avoidance of undue working are aided by increasing the cross-sectional dimensions of the chamber 18 after the orifice 14 and as necessary by warmingthe chamber 18 and coupling arrangement 19 externallyby warm water flowing in jacket 15. After crystallisation is effectively completed in the chamber 1 8 the i cryst-allised material passes to the coupling arrangement 19 and'jthen to thepacking machine 20. Both the coupling; arrangement 19 and packing machine 20 operate as described in British Patent No. 590,935 and the wrapped packets are conveyed from the machine 20 by conveyor 21.

As illustrative of the above invention the above described procedure was carried out with a blend of fat containing 40% coconut oil, 30% hardened beef fat and 30% cottonseed oil. The following Table I gives operating conditions in the case of four runs with this blend of fat, in all of which runs a wrapped satisfactorily aerated cooking fatwas obtained.

Table I Trial No 1 2 3 4 Fat Blend Temperature I 0. 46 43 42. 5 42 Pressure in tubes 13 and 13 (kilos/square cm.)-. 11-12 12. 5-14. 17.6-19. 12-22 Temperature of roduct from tube 13' O.)--.. 17.8 17. 2 16. 7 16 Pressure in chamber 18 (kllos/sguare cm.)..-... 0. 35-0. 70 0-0. 35 0.350.85 0.35-1.05 Entraine air content value (voL/vol.) of the end product (percent).. 11 8 10. 5 9. 4 Air pressure on piston of coupling device 19 (kilos/square cm.).-.--. 1. 4 1. 4 1. 4 1. 4 Temperature of water through Jacket 15 0.)- 37 37 37 37 Quick setting blends of fat facilitate processing procedure, but variations in blend composition may be accommodated by adjustment of chilling conditions in tubes 13 and 13' with corresponding alteration in pressure differential across the gate valve 14 Generally, with slower setting blends a lower product temperature from the chilling tubes than given in Table I above is necessary with a corresponding adjustment of the gate valve to give an increased pressure differential across it and so ensure the desired expansion of the product at the lower temperature. Chamber 18 may be altered in length to vary the setting period, depending upon the setting point of the product and to ensure that crystallisation is effectively complete when the product reaches the wrapping machine 20.

We claim:

1. A continuous process of producing and packing an aerated shortening which includes the steps of aerating liquid fat with an innocuous gas, chilling the stream of aerated fat, crystallizing the fat and feeding the stream of crystallized fat to an automatic packing machine, said fat being subjected to a pressure between and 25 kilos per sq. cm. above atmospheric pressure during said chilling'stepand to a pressure less than 1.5 kilos 'persq. cm. above atmospheric pressure during at least a portion of the crystallizing step, the pressure difference being created by constricting the stream of chilled fat before crystallization is completed and by allowing the fat stream to expand suddenly in the crystallization chamber before crystallization has substantially completed.

2. A continuous process of producing and packing an aerated shortening which includes the steps of aerating liquid fat with an innocuous gas, chilling the stream of aerated fat, crystallizing the fat, feeding the stream of crystallized fat to an automatic packing machine and warming the surfaces of the stream of crystallized fat being fed to the packing machine, said fat being subjected to a pressure between 10 and 25 kilos per sq. cm. above atmospheric pressure during said chilling step and to a pressure of less than 1.5 kilos per sq. cm. above atmos pheric pressure during at least a portion of the crystallizing step, the pressure difference being created by con:

" stricting the stream of chilled fat before crystallization is completed and by allowing the fat stream to expand suddenly in the crystallization chamber before crystallization has substantially completed.

3. A continuous process for producing and packing an aerated shortening which comprises aerating a stream 'of liquid fat with an innocuous gas, chilling the stream of aerated fat under pressure, crystallizing the stream of chilled aerated fat and feeding it to an automatic packing machine, said stream of fat undergoing a rapid reduction in pressure before crystallization is substantially complete to cause the dissolved gas to change from the dissolved to the entrained state, said pressure on the chilled aerated fat before the pressure reduction step being sufficiently high to retain the gas in the shortening in a dissolved state, and said pressure on the chilled aerated fat after the pressure reduction step being less than 1.5 kilos per sq. cm. above atmospheric pressure, and sufficient to maintain a substantial proportion of the gas in the entrained state.

4. A process as claimed in claim 3 in which the pressure is relieved almost immediately after the cessation of the chilling step.

5. A process as claimed in claim 3 in which the pressure on the fat during chilling is between 10 and 25 kilos per sq. cm. and the pressure during crystallisation is less than 1.5 kilos/sq. cm.

6. A process as claimed in claim 3 in which the pressure conditions are established by suddenly constricting the stream of fat before crystallisation is completed, and in which the pressure is thereafter relieved by suddenly expanding said stream of fat.

7. A process as claimed in claim 3 in which the surfaces of the crystallised fat stream are warmed before the crystallised fat is packed.

8. An arrangement for producing an aerated shortening which includes means for introducing an innocuous gas into liquid fat, a chilling device connected thereto for chilling the stream of liquid fat, a crystallising device in which the chilled fat is allowed to crystallise, a connection between the chilling device and the crystallising device, a constriction in said connection, an intermittently operating packing machine, a connection between the packing machine'and the crystallising device and pressure means for applying additional pressure to any material in the connection between the packing machine and the crystallising device serving to accommodate the material issuing from the crystallising device during the period of closure of the packing machine.

9. An arrangement as claimed in claim 8 including means for adjusting the dimensions of the constriction.

10. An arrangement as claimed in claim 8 in which the constriction is provided by a gate valve.

11. An arrangement as claimed in claim 8 in which the chilling device comprises a hollow, cooled cylinder having a plurality of scraper blades mounted for rotation therein.

12. An arrangement as claimed in claim 8 in which the means for introducing the innocuous gas is a needle valve connected to a conduit connecting the chilling device to a source of liquid fat.

13. An arrangement as claimed in claim 8 in which the pressure means is arranged to apply pressure while the packing machine is open to be charged and to re lease the pressure while the packing machine is closed.

14. Anarrangernent as claimed in claim 8 in which the crystallising device and the connection between the packing machine and the crystallising device are provided with external heating means.

15. An arrangement for producing an aerated shortening which includes a source of liquid fat, a chilling device comprising a hollow, cooled cylinder having a plurality of scraper blades therein, a conduit connecting the source of liquid fat and the chilling device, a needle valve, a conduit connecting the needle valve to the conduit connecting the chilling device and the source of liquid fat, a crystallising device, a connection between 20 the crystallising device and the exit of the chilling device, a gate valve in said connection, an intermittently operating packing machine, a connection between the crystallising device and the packing machine, means for externally heating the connection between the crystallising device and the packing machine and pressure means for applying additional pressure to any material in theconnection between the crystallising device and the packing machine while the packing machine is open tobe charged and for releasing the pressure while the pack ing machine is closed, said pressure means serving to ac commodate the output of the setting machine during the period of closure of the packing machine.

16. A continuous process of producing and packaging an aerated shortening which comprises placing a stream of chilled, aerated liquid fat under a high pressure, crystallize ing the stream of chilled, aerated fat, and suddenly releas ing substantially all of said pressure before crystallization is complete.

References Cited in the file of this patent UNITED STATES PATENTS 2,063,065 Voget et a1. Dec. 8, I936 2,206,419 Miller July 2, 1940 2,223,724 Godfrey et al. Dec. 3, 1940 2,330,986 Miller et al. Oct. 5, 1943 2,395,051 Horeneman et al Feb; 19, 1946 2,728,674 Griflin et al. Dec. 27, 1955 UNITED STATES PATENT OFEICE CERTIFICATE OF CORRECTION Patent No 2 882 165 April 14, 1959 William Dalzie'l ale It is hereby certified that error appears in the printed specification of tlde' above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, line 45 for mannine" read we column 3, line 23 for "packing" read paokaging line 65 for "in provided" read We is provided column 4., line 61y for "War Water" w Warm Water column 5, Table l fifth column thereof second item; for "lZ ZPl" read PM 211M2 2 we; same column 5;, line 57,: after the numeral "14" insert a period; column 8;, line 19, list of references cited for "Voget at all," read 3.1:;

Signed and sealed llth day of August 1959,

KARL H, AXLINE Attesting Oificer ROBERT C. WATSON Commissioner of Patents 

8. AN ARRANGEMENT FOR PRODUCING AN AERATED SHORTENING WHICH INCLUDES MEANS FOR INTRODUCING AN INNOCUOUS GAS INTO LIQUID FAT, A CHILLING DEVICE CONNECTED THERETO FOR CHILLING THE STREAM OF LIQUID FAT, A CRYSTALLISING DEVICE IN WHICH THE CHILLED FAT IS ALLOWED TO CRYSTALLISE, A CONNECTION BETWEEN THE CHILLING DEVICE AND THE CRYSTALLISING DEVICE, A CONSTRICTION IN SAID CONNECTION, AN INTERMITTENTLY OPERATING PACKING MACHINE, A CONNECTION BETWEEN THE PACKING MACHINE AND THE CRYSTALLISING DEVICE AND PRESSURE MEANS FOR APPLYING ADDITIONAL PRESSURE TO ANY MATERIAL IN THE CONNECTION BETWEEN THE PACKING MACHINE AND THE CRYSTALLISING DEVICE SERVING TO ACCOMMODATE THE MATERIAL ISSUING FROM THE CRYSTALLISING DEVICE DURING THE PEIOD OF CLOSURE OF THE PACKING MACHINE.
 16. A CONTINUOUS PROCESS OF PRODUCING AND PACKAGING AN AERATED SHORTENING WHICH COMPRISES PLACING A STREAM OF CHILLED, AERATED LIQUID FAT UNDER A HIGH PRESSURE, CRYSTALLIZING THE STEAM OF CHILLED, AERATED FAT, AND SUDDENLY RELEASING SUBSTANTIALLY ALL OF SAID PRESSURE BEFOR CRYSTALLIZATION IS COMPLETE. 